TITLE: GCN CIRCULAR
NUMBER: 18737
SUBJECT: LIGO/Virgo G211117: INTEGRAL was inactive at the time of the event
DATE: 15/12/28 17:36:51 GMT
FROM: Volodymyr Savchenko at APC,Paris
V. Savchenko (APC, Paris, France), S. Mereghetti (IASF-Mi, Italy),
C. Ferrigno, E. Bozzo (ISDC, University of Geneva, CH) ,
E. Kuulkers (ESAC/ESA, Madrid, Spain), on behalf of a larger collaboration
The INTEGRAL spacecraft has a highly elliptical orbit and the instruments
are switched off around the perigee passage, every 2.6 days, to prevent
radiation induced damages. Unfortunately, at the time of the LIGO/Virgo
trigger G211117 (2015-12-26 03:38:53 UTC) the spacecraft was close
to the perigee between the orbits number 1625 and 1626. The data
from the anti-coincidence monitor are not available from 2015-12-25 20:57
to 2015-12-26 07:46 UTC. Yet, the narrow-field hard X-ray instruments
of INTEGRAL were pointing to the Cygnus region when the operations
resumed at 2015-12-26 07:59 (about 4.5 hours after the trigger), too far
from the trigger high probability zones to yield any meaningful limit on
possible
long-lasting electromagnetic counterparts of the gravitational wave
trigger.